"IMSCREWS 5/16 x 3-1/2 Heavy-Duty Lag Screws - 304 Stainless Steel (10 pcs)
Deep Reach for Structural Timber Connections When your project demands deep penetration and unyielding holding power, these 3.5-inch lag bolts provide the industrial strength needed. Optimized for securing deck railing posts, heavy gate frames, or structural brackets to 4x4 posts. The 5/16 diameter offers elite shear resistance for critical load-bearing joints.
Vise-Like Clamping with Partial Threading Our partially threaded shank features a smooth upper section that allows the bolt to pull the outer timber tightly against the support beam. This creates a gap-free, rock-solid joint, eliminating the bridging effect where boards remain loose—a common failure in long full-thread screws for structural framing.
304 Stainless Exterior Defense Forged from premium 18-8 (304) Stainless Steel for ultimate weather resistance. compatible with ACQ pressure-treated lumber. Resists rust in humid environments and prevents unsightly rust streaks on high-value cedar, redwood, or deck framing.
Technical FAQ • Tools Required: Fits a standard 1/2 hex socket or wrench. • Pre-drilling: Recommended to prevent timber splitting. Use a 3/16 bit for softwoods or 7/32 bit for hardwoods. • Why 3-1/2 length? Perfect for passing through 1.5 or 2 timber with a deep 1.5 + thread anchor in the base post. • Resilience: Rated for marine, coastal, and high-humidity environments.
ELITE CLAMPING POWER The partially threaded design ensures the smooth shank stays in the outer board, allowing the threads to pull timber members together with immense force for a gap-free joint.
IDEAL FOR 2x4 TO POSTS At 3.5 inches long, these screws provide the perfect structural anchoring depth for connecting standard 2x lumber to 4x4 or 6x6 posts without over-penetration.
304 EXTERIOR DEFENSE Forged from premium 304 (18-8) stainless steel to prevent rust and staining in cedar, redwood, or ACQ pressure-treated lumber projects.
STABLE TORQUE INTERFACE Precision-forged hex head fits 1/2 sockets securely, offering stable torque transfer for controlled, slip-free seating even in dense timber cores.
TECHNICAL SPECIFICATION To prevent timber splitting from the robust 5/16 diameter, pre-drilling a pilot hole (7/32 for softwoods, 1/4 for hardwoods) is mandatory.